Art of artificial sound reproduction



Oct. 8, 1929. H. s. HELLER 1,730,611

ART or ARTIFICIAL scum) REPRODUCTION Filed 001:. 9, 1926 & E g k g g Q Q 2 m l Ill/ I ll/ 5 Q E a 4 k E Q\ g\ k) s: 2?: z

\ /m/e/220rv Patented Oct. 8, 1929 UNITED STATES PATENT OFFICE HERMAN s. HELILER, or NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, To ELECTRICAL RESEARCH PRODUCTS, INC., A CORPORATION or DELAWARE ART OF ARTIFICIAL SOUND REPRODUCTION Application filed October 9, 1926. Serial No." 140,556.

recording apparatus orchestral, choral and operatic music, and the like. J

As Well known, in phonographic recording systems, sounds are transmitted from the stage or studio where the performer is located, to the recording apparatus through flatness of one made with a single microthe agency of microphones with or without the aid of amplifiers. If several performers (e. g., an orchestra, a chorus, etc.) appear on the stage, it is often desirable to arrange a plurality ofmicrophones so that all the details of the music be properly transmitted to the recorder. A single microphone located at a fixed point cannot always be relied upon uniformly to intercept the sounds coming from various parts of the stage and from various performers or instruments.

In accordancewith the present invention,

two or more microphones are positioned in the studio. The number of microphones and their location will, of course, be dependent on the character of the music, song, etc., to'

be recorded, onthe acoustics of the studio, on the taste of the musical director, etc. By connecting a plurality of such microphones with the recorder, preferably through an amplifying system, a record could be made of all the details of the performance. However, while such a record would not have the phone, it would have many other drawbacks quite as serious. The object is to make a record, e. g., of an orchestral performance which," when reproduced by artificial means, such as telephone, lo'ud speaker, phonograph, or the like, will make substantially the same impression on an. audience as the audition of the original performance. A microphone located above the wind instruments, a second microphone located above the string instruwould be conveyed through the air and by reflection from the walls of an opera house or concert hall to one located at a certain distance from the orchestra. The field of one microphone would necessarily overlap that of another, soundsmade by certain instruments or singers are more readily transmitted than those made by others and, generally, the blending of the sounds would be only approximated. A single microphone could be used for recording with better results as far as blending is concerned than a plurality of microphones.

With this in View the present invention provides for the method of phonographically recording the output of a plurality of microphones which comprises the step of varying the output of each microphone in accordance with predetermined score markings.

-Before the artificial reproduction or recordingof the music or the like can be per-' formed, a score must be prepared on which, in addition to the usual musical notations, markings appear in accordance with which the output of each microphone must be controlled during various passages of the music or various phases of the performance. .By' providing a suitable mechanism whereby, for the whole duration of an orchestral performance or from time to time, the output of one microphone may be subdued or enhanced with respect to that of another in accordance with said markings, it is possible to record or artificially produce music, so that the impression of an original audition be created.

Inaccordance with the present invention, this is accomplished by connecting an amplifying system in series with the reproducing equipment and by associating all the microphones in parallel with this amplifier. I provide a controller such as a variable resistance in the circuit of each microphone which may be so adjusted as to control the output of the associated microphone. s v

First, the number and location of the microphones must be determined and then the music is transmitted through them to a telephone receiver located at a distant place."

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output of the-various microphones should be controlled and makes the notations or markings necessary on the score. These notations will be to the effect that during a certain passage the output of, let us say, three microphones should be limited to w, y, z, and during a second passage the output of the same microphones should be 2, 7 02, etc. After the whole score has been marked in this manner, the orchestra is ready to play for recording or artificial reproduction. A person located near the telephone receiver and'having accessible the microphone output controls will follow the performance on a marked copy of the score and will set the controls in accordance with the notations, so that the input circuit of the recorder or reproducerreceives October, 1926.

' HERMAN S. HELLER.

the music blended in accordance with the ter of tl e p erformance'and the mechanical and elec xical equipment employed. To a certain ex entit will depend also on the place .where the reproduction will be heard. It is possible to bring out any part of a musical performance, to accentuate the singing of a soloist accompanied by an orchestra, etc.

For the purpose of illustrating the manner in which the invention may be practiced, the drawings show schematically the general arrangement of phonographic recording equipment without, however, indicating the details which are immaterial for an understanding of the present invention.

Three separate rooms are illustrated, the studio, the control room and the recording room. Two microphones located in the studio are connected with an amplifier located in the recording room and the latter is connected with the recorder. In the control room a variable resistance A, B is provided in the circuit of each microphone. The setting of a variable resistance will determine the output of the associated microphone into the amplifier. The output circuit of the amplifier is connected with a telephone receiver also located in the control room. The operator stationed in the control room attends to the setting of the variable resistances A, B and others, if there are more microphones, in

accordance with the markings on the score,

whereby the output of each microphone into 

